U.S. Pat. No. 4,839,501 issued Jun. 13, 1989 to Cowell entitled "Cartridge Soldering Iron" discloses a cartridge soldering iron having a handle and a soldering iron held in the handle. In a high frequency induction heating soldering iron of the Curie temperature control type such as the one disclosed in the '501 patent, the heating tip must be replaced according to the desired soldering temperature so that the temperature to be obtained corresponds with the Curie temperature of the tip material. Hence, the soldering iron of the '501 patent requires soldering tips made of different materials having different Curie temperatures depending on the desired temperatures. A number of required replacement tips is high for a conventional soldering iron utilizing the Curie temperature controlled tips which increases the required processing steps and time, and adds to the overall cost of soldering.
FIG. 6 shows a graph of tip temperatures against time in a conventional soldering iron. For achieving a target temperature of 400.degree. C. a contentional soldering iron takes about 60 seconds. Further, a temperature variation after achieving the target temperature reaches as much as 85.degree. C.